Fume exhauster for tiltable furnaces



g- 5, 1952 K. s. LlNDH ET AL 2,606,016

FUME EXHAUSTER FOR TILTABLE FURNACES Filed Oct. 14; 1948 2 SHEETS-SEET 1 lA/VWORS mm. STL/RE L/NDH and,

KURT 745E TL/RESSON 8y: WWW

2 SHEETS-SHEET 2 K. S. LINDH ETAL FUME EXHAUSTER FOR TILTABLE FURNACES Filed Oct. 14, 194

Patented Aug. 5, 1952 "UNITED STATES PATE T omcr.

FUME EXHAUSTER FOR TILTABLE FURNACES KarlSture Lindli and Kurt Tage Tureson, Stockholm, Sweden, assignors to A. B.- Svenska Flaktfabrikemstockholm', Sweden Application October 14, 1948, Serial No. 54,416

I In Sweden October 16, 1947 2 Claims. 1

The present invention relates to a device for preventing smoke 'or gases from the melt in smelting furnaces, particularly in high-frequency furnaces or other induction furnaces, from emerging into the surrounding premises.

In smelting furnaces, which are open at the top, either such furnaces are stationary, rotatable or in any other way tiltable, it is before known that smoke and gas will develop from the melt and rise in the premises surrounding the furnace, where they have a disturbing effect on the labourers. In case thegases are poisonous, as for instance when melting zinc or in case carbon monoxide is developed, they will be injurious to 'the health of the operators, but if this should not be the case it will still be unpleasant to dwell in such surroundings, and the gases willcause illnesses periodically, which illnesses also in case they can be fully cured, still have. a disturbing effect on the working of the plant- The same disadvantages occur also in furnaces provided with a cover over the aperture thereof. The cover is removed, for instance, when pouring takes place, and the smoke and gases will then escape into the premises. Furthermore the cover is removed, when the furnace is charged with fresh melting material. In case this comprises, for instance, working particles rich in oil, an intense smoke and gas development'will take place in the premises. However, it is not always necessary to remove the cover from the furnace, as certain furnaces are provided with specialopenlugs for the discharge of the melt and with other openings for skimming of the surface of the melt and for the introduction of fresh melting'material. If such apertures are provided the smoke and gases will also escape through these into the premises. Thus, it is desired in furnaces open at the top as well as in furnaces provided with covers to prevent the emerging of the smoke and gases from the furnace to the premises.

The furnaces which are open at the top generally work continuously melt being discharged alternately with the charging of fresh melting material. The melting material is introduced into the opening of the furnace and the surface of the melt is skimmed from time totime from slag by means of a slag ladle inserted through the hole. If the furnace is rotatable or tiltable the melt is often tapped directly through the furnace hole. Thus furnaces that always are open at the top particularly require something that prevents the smoke and gases from escaping, but this becomes true also with respect to most otherfurnace types.

The object of the present invention is to eliminate or at least to diminish said drawbacks in furnaces.

The method according to the invention is characterized by the fact that the smoke or gases are sucked out from the furnace at its top rim by means of a suction device in one or more currents directed outwards from the top rim of the furnace and substantially parallel with same.

The arrangement for accomplishing said method is characterized by the fact that one or more encircling casings connected to a suction device are arranged at the top rim of the furnace in the plan thereof and along the greater portion of the furnace top rim and are provided with one or more suction holes extending circumferentially around the furnace hole. Other fea-' tures characterizing the device according to the invention will be seen by some embodiments described by way of example in connection with the accompanying drawings.

Two embodiments of the device according to the invention are shown in the annexed drawings, in which Figures 1 and 2 show a vertical and a horizontal section, respectively, of a high frequency furnace having a smoke suction device according to the invention, and Figures 3 and 4 show a vertical and a horizontal section, respectively, of a high-frequency furnace having another such arrangement. a

Figure 1 is a section of Figure 2 along, line I-I, Figure 2 a section of Figure 1 along line II-II, Figure 3 a section of Figure 4 along line IIIIII, and Figure 4 a section of Figure 3 along line IV-IV.

Figures 5 and 6 are details of Figure 1 shown on a larger scale.

The smelting furnace according to- Figures 1 and 2 comprises a supporting structure It of the furnace, which supporting structure is provided with two journals II and i2 pivotally mounted in bearing casings l3 and I4 solidly arranged in the masonry l5 surrounding the furnace. The furnace consists in addition of a bottom plate It and a furnace lining I'l ending in a rim is at the top. At the upper end ofthe furnace there is arranged a tapping outlet l9 and a slag outlet Zll. The furnace as a whole is arranged in a pit 2! formed by the masonry [5. The furnace may be pivoted inthe pit 2| about, its pivots H and I2 in order todischarge melt. Two casings 22 and 23 are arranged right opposite each other on the furnace and on either side of the tapping outlet point I9 and the slag outlet 20. The casings 22 and 23 are secured to the furnace in the same plane as its top rim l8 and extend along the rim around the greater portion of the furnace hole 24. The circumferential surfaces of the casings facing the furnace hole are provided with suction holes 25 and 25. The furnace lining forms throttling devices 21 and 28 extending from the top rim |8 into the holes 25 and 26. respectively, and reduce these. The upper surfaces of the casings are plane and form a hearth on top of the furnace. This hearth is reinforced by means of stays, of which only the stays 29 and 30 are seen in Figure 1. V tions of the casings facing the furnace hole generally only extend to the extension of the likewise plane at the top and provided with reinforcements, of which only the reinforcements 29 and 30 are to be seen in Figure 3. The side of the casing facing the furnace mouth 24 is provided with an opening 48 extending circumferentially alongthe furnacemouth, which opening'is throttled by the throttling member 49. The upper portion of the casing is provided with a facing 5|] along the opening 48. The portions of the drum facing the furnace mouth 1 extend generally only to the extension of the The por-- interior cavity 3| of the furnace. and the holes and 26 of the casings are provided with a facing 32. The ends 33 and 34 of the outlet portions of the two casings 22 and 23 are so advanced that they terminate in planes perpendicular tothe axis of the pivots II and |2, and co-axially with the same, one at each pivot II and I2, respectively. The end 33 of the outlet portion of the casing 22 is more clearly seen by Figure 5. A packing device is arranged around the outlet end 33 of the casing and comprises a sleeve 35 enclosing the outlet end, which sleeve is provided with slots 33 for pins 31, by means of which the packing is adjustably secured in various axial positions relative to the casing. The sleeve 35 is provided with a radial flange 38 which jams an annular packing 4| of rubber fabric or any other suitable material by means of pins 40, in-between said. flange and a collar 39. The packing device cooperates with the end of a fixedly arranged discharge duct 42, which is connected to a suction device (not shown). The end of the discharge duct 42 is provided with a fiat collar 43'facing the packing 4|, which collar constitutes the part of the discharge duct 42 'co'-acting with the packing 4|. By the structure described it will be seen that the packing 4| rotates about the collar 43 when the furnace pivots about its pivots H and 12 whereby the casing 22 remains connected to the suction device when the furnace is tilted. The casing 23 is in a corresponding way connected tothe same or another suction device.

From the described arrangement will be understood that, when the furnace is workin smoke and gases from. a layer across the furnace at its top is sucked out through the casings and prevented'from passing out into the premises and disturbing the furnace operators in their work. r

The throttling members 21 ad 28 serve to divide the suction effect from the casings evenly along the holes 25, 26 of the casings facing thefurnace. There may be one or more holes for each casing.

The furnace illustrated in Figures 3 and 4 is of the same make as the one described with reference to Figures 1 and 2, and thus the same reference characters have been used for the furnace structures in, both cases. The device according to the invention shown in Figures 31 only provided one. casing 44 forming two arms,

45 and 46 provided with a common discharge end 41. The arms extend around the furnace top rim in plane therewith, and end at either side of thetapping point I9. This casing is The discharge hole with a flat annular flange 5| which, bears with a negligible clearance on the wall in the pit 2| right infront of an outlet channel 52 arranged in the same and which communicates with a suction device (not shown). The discharge end 41 and the channel 52 are reciprocally so located that they maintain a connection with one another, when the furnace takes its vertical position for melting. When on the other hand the furnace is tilted for tapping the melt the connection between the discharge end 41 and the channel 52 is interrupted. This means that smoke and gases from the melt are not sucked out from the'furnace as long as the tapping takes place but only when no discharge of the melt occurs. In the furnace shown in Figures 1 and2 the suction of smoke and gases from the furnace occurs all the time the furnace operates, as the connection between the outlet drums 42 and the drums 22 and 23 is not interrupted during the tapping of the melt.

The furnace of both Figures 1 and 2, and Fig- 'ures 3 and 4 is provided with electric windings extending around the sarrie"'and effecting the melting and with cooling coils placed in-between them'which are both designated by 53.

The device illustrated in Figures 3 and 4 acts in such a way that smoke and gas are sucked away in a horizontal layer at the top of the furnace through the casing 44 and the channel 52 of the suction device (not shown).

The invention may be modified within wide limits and be applied to smelting furnaces having a cover or not. When applied to stationary furnaces, the casings or casing may be solidly connectedto the discharge casings or discharge channels. With stationary furnacesthere are in this case meant smelting furnaces that are not tiltable, either the tilting takes place by rotation about a shart or byrolling. I Having now described our invention, what we claim as new, and desire to secure by United States Letters 1 Patent, is:

1 device for the removal of noxious fumes from a melting pot or the ;like comprising: an upright substantially cylindrical melting pot having a pouring lip at'its upper edge and tiltable about a substantially horizontal axis for pouring; a suction casing attached'to the pot and extending substantiallyaround the upper-rim thereof on-each side of .the-lip, said'ca ing having an upperwall overhanging the upper rim of the pot and terminating substantially in alignment with the interior diameter of the pot to provide an access opening; restricting means in said casing between the pot and the upper wall substantially in alignment with the interior diameter of the pot toprovide a throttled connection at the interior'diameter of the pot between the pot and easing whereby a high-velocity air stream is' directed from the center of the pot opening substantially horizontally to said throttled connection to prevent escape of vapors from the pot; said casing having at least one duct extending laterally in the general direction of the tilting axis and terminating in a plane substantially perpendicular to the tilting axis; and a suction supply duct separate from the first duct and ar ranged substantially in alignment therewith.

2. A device for the removal of noxious fumes from a melting pot as specified in claim 1 wherein said first mentioned direct terminates c0- axially with the tilting axis of the pot; and the suction supply duct is connected by a swivel joint to the first duct.

KARL STURE LINDH. KURT TAGE TURESGN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

